Your computer is more than fine!
OK, so it won't play modern games at high res with all the eye candy. Other than that, it's MORE than sufficient for gaming, surfing, office work, photoshop, etc.
If forced to file a 'complaint,' I'd point to the stripped down Audigy SE (shame on Creative for abusing the Audigy brand) The card lacks a 'real' hardware sound processor and is more akin to the on-board chips found on most motherboards.
http://en.wikipedia.org/wiki/Sound_Blaster_Audigy#Sound_Blaster_Audigy_2_SE It's not awful, but will put more load on the CPU than a 'real' Audigy(2) would. The
only time this will matter is when playing games with lots of sound sources enabled.
When/if you run out of storage, a newer/faster HD might speed things up noticeably. (What are you running now?) In my experience, the 'migration' utilities work flawlessly, transferring your OS, apps, etc. to the new HD without disturbing a thing.
FWIW. Apart from this modest Socket A rig, I've got two old XP-M (AMD low power mobile chip) based computers hanging about. One is overclocked a little, stuffed 3G of ram, (performance slightly better than your beast) and is dedicated to digital image editing. It drives my film scanner and does just fine photoshopping and tweaking the resultant monster files. The other computer is hooked to the stereo, and spends its days running a digital jukebox. The poor thing must be bored to tears.